In order to advance the world step, we have to call the step function in the world instance periodically. We used setTimeout to keep calling the step function. Put the following function in our JavaScript logic file:

function updateWorld() {
  // Move the physics world 1 step forward.
  carGame.world.Step(1/60, 10, 10);

  // display the build-in debug drawing.
  if (shouldDrawDebug) {
    carGame.world.DrawDebugData();
  }
}

Next, we will set up an interval in the initGame method:

setInterval(updateWorld, 1/60);

We will again simulate the world in a browser. The box is created at the initialized position and falls on the ground correctly. The following screenshot shows the sequence of a box dropping on the ground: